The U.S. Supreme Court considered in oral arguments on Monday whether judges, rather than jurors, may find facts that raise a mandatory minimum sentence.

In a “combative discussion,” the justices considered the reach of a case dealing with maximum sentences, Apprendi v. New Jersey, SCOTUSblog reports. The 2000 decision said the Sixth Amendment right to a jury trial bars judges from increasing prison sentences beyond the statutory maximum based on facts that aren’t submitted to a jury.

At issue is whether to overrule a decision issued two years later, Harris v. United States, that allowed judges to find facts that raise the minimum using a preponderance of the evidence standard. The justices appeared narrowly divided on the issue, Reuters reports in its story on the arguments.

SCOTUSblog says the new case, Alleyne v. United States, “is a potentially historic dispute over the modern phenomenon of ‘mandatory minimun’ sentences, and the roles of judges and juries in imposing such sentences.”

The petitioner, Allen Alleyne, was facing a mandatory minimum of five years in prison for robbing a convenience store when a judge found the defendant had brandished a gun, raising the minimum to seven years. Alleyne’s lawyer, assistant federal public defender Mary Maguire of Richmond, Va., urged the court to overrule Harris because only a plurality of justices agreed fully with its reasoning, Reuters says.

“You are stripping the defendant of the full benefit of the full jury verdict,” Maguire told the court.